Now, we arrived modprobe config. Old versions of Centos/Redhat bonding configurations should be set with /etc/modprobe.conf but with Centos6 its little different. You have to get in /etc/modprobe.d folder and create a file like below

vi /etc/modprobe.d/bonding.conf

alias bond0 bonding
options bond0 mode=balance-alb miimon=100

Be sure that cables are connected to nics

You can find on some articles like modprobe bonding and restart the service network, these are not worked for me , pls try to restart server